我一直在尝试将从图像创建的 H264 视频流设置到 MPEG4 容器中。我已经能够成功地从图像中获取视频流。但是当在容器中混合它时，我必须做错事，因为没有播放器能够重现它，尽管 ffplay - 播放视频直到最后，然后图像被冻结直到永恒 -。
ffplay 无法识别 Duration 和比特率，所以我认为这可能是与 dts 和 pts 相关的问题，但我已经搜索了如何解决它但没有成功。
这是ffplay的输出：
~$ ffplay testContainer.mp4
ffplay version git-2012-01-31-c673671 Copyright (c) 2003-2012 the FFmpeg developers
built on Feb 7 2012 20:32:12 with gcc 4.4.3
configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable- libfaac --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-x11grab --enable-libvpx --enable-libmp3lame --enable-debug=3
libavutil 51. 36.100 / 51. 36.100
libavcodec 54. 0.102 / 54. 0.102
libavformat 54. 0.100 / 54. 0.100
libavdevice 53. 4.100 / 53. 4.100
libavfilter 2. 60.100 / 2. 60.100
libswscale 2. 1.100 / 2. 1.100
libswresample 0. 6.100 / 0. 6.100
libpostproc 52. 0.100 / 52. 0.100
[h264 @ 0xa4849c0] max_analyze_duration 5000000 reached at 5000000
[h264 @ 0xa4849c0] Estimating duration from bitrate, this may be inaccurate
Input #0, h264, from 'testContainer.mp4':
Duration: N/A, bitrate: N/A
Stream #0:0: Video: h264 (High), yuv420p, 512x512, 25 fps, 25 tbr, 1200k tbn, 50 tbc
2.74 A-V: 0.000 fd= 0 aq= 0KB vq= 160KB sq= 0B f=0/0 0/0
结构
我的代码是 C++ 风格的，所以我有一个处理所有编码的类，然后是一个对其进行初始化的 main，在一个 bucle 中传递一些图像，最后通知进程结束，如下所示：
int main (int argc, const char * argv[])
{
MyVideoEncoder* videoEncoder = new MyVideoEncoder(512, 512, 512, 512, "output/testContainer.mp4", 25, 20);
if(!videoEncoder->initWithCodec(MyVideoEncoder::H264))
{
std::cout << "something really bad happened. Exit!!" << std::endl;
exit(-1);
}
/* encode 1 second of video */
for(int i=0;i<228;i++) {
std::stringstream filepath;
filepath << "input2/image" << i << ".jpg";
videoEncoder->encodeFrameFromJPG(const_cast<char*>(filepath.str().c_str()));
}
videoEncoder->endEncoding();
}
提示
我看过很多关于解码视频和编码到另一个视频的例子，但没有从头开始混合视频的工作例子，所以我不确定如何处理 pts 和 dts 数据包值。这就是为什么我怀疑问题必须在以下方法中的原因：
bool MyVideoEncoder::encodeImageAsFrame(){
bool res = false;
pTempFrame->pts = frameCount * frameRate * 90; //90Hz by the standard for PTS-values
frameCount++;
/* encode the image */
out_size = avcodec_encode_video(pVideoStream->codec, outbuf, outbuf_size, pTempFrame);
if (out_size > 0) {
AVPacket pkt;
av_init_packet(&pkt);
pkt.pts = pkt.dts = 0;
if (pVideoStream->codec->coded_frame->pts != AV_NOPTS_VALUE) {
pkt.pts = av_rescale_q(pVideoStream->codec->coded_frame->pts,
pVideoStream->codec->time_base, pVideoStream->time_base);
pkt.dts = pTempFrame->pts;
}
if (pVideoStream->codec->coded_frame->key_frame) {
pkt.flags |= AV_PKT_FLAG_KEY;
}
pkt.stream_index = pVideoStream->index;
pkt.data = outbuf;
pkt.size = out_size;
res = (av_interleaved_write_frame(pFormatContext, &pkt) == 0);
}
return res;
}
任何帮助或见解将不胜感激。提前致谢！！
PS 完成配置的其余代码如下：
// MyVideoEncoder.cpp
#include "MyVideoEncoder.h"
#include "Image.hpp"
#include <cstring>
#include <sstream>
#include <math.h>
#define MAX_AUDIO_PACKET_SIZE (128 * 1024)
MyVideoEncoder::MyVideoEncoder(int inwidth, int inheight,
int outwidth, int outheight, char* fileOutput, int framerate,
int compFactor) {
inWidth = inwidth;
inHeight = inheight;
outWidth = outwidth;
outHeight = outheight;
pathToMovie = fileOutput;
frameRate = framerate;
compressionFactor = compFactor;
frameCount = 0;
}
MyVideoEncoder::~MyVideoEncoder() {
}
bool MyVideoEncoder::initWithCodec(
MyVideoEncoder::encoderType type) {
if (!initializeEncoder(type))
return false;
if (!configureFrames())
return false;
return true;
}
bool MyVideoEncoder::encodeFrameFromJPG(char* filepath) {
setJPEGImage(filepath);
return encodeImageAsFrame();
}
bool MyVideoEncoder::encodeDelayedFrames(){
bool res = false;
while(out_size > 0)
{
pTempFrame->pts = frameCount * frameRate * 90; //90Hz by the standard for PTS-values
frameCount++;
out_size = avcodec_encode_video(pVideoStream->codec, outbuf, outbuf_size, NULL);
if (out_size > 0)
{
AVPacket pkt;
av_init_packet(&pkt);
pkt.pts = pkt.dts = 0;
if (pVideoStream->codec->coded_frame->pts != AV_NOPTS_VALUE) {
pkt.pts = av_rescale_q(pVideoStream->codec->coded_frame->pts,
pVideoStream->codec->time_base, pVideoStream->time_base);
pkt.dts = pTempFrame->pts;
}
if (pVideoStream->codec->coded_frame->key_frame) {
pkt.flags |= AV_PKT_FLAG_KEY;
}
pkt.stream_index = pVideoStream->index;
pkt.data = outbuf;
pkt.size = out_size;
res = (av_interleaved_write_frame(pFormatContext, &pkt) == 0);
}
}
return res;
}
void MyVideoEncoder::endEncoding() {
encodeDelayedFrames();
closeEncoder();
}
bool MyVideoEncoder::setJPEGImage(char* imgFilename) {
Image* rgbImage = new Image();
rgbImage->read_jpeg_image(imgFilename);
bool ret = setImageFromRGBArray(rgbImage->get_data());
delete rgbImage;
return ret;
}
bool MyVideoEncoder::setImageFromRGBArray(unsigned char* data) {
memcpy(pFrameRGB->data[0], data, 3 * inWidth * inHeight);
int ret = sws_scale(img_convert_ctx, pFrameRGB->data, pFrameRGB->linesize,
0, inHeight, pTempFrame->data, pTempFrame->linesize);
pFrameRGB->pts++;
if (ret)
return true;
else
return false;
}
bool MyVideoEncoder::initializeEncoder(encoderType type) {
av_register_all();
pTempFrame = avcodec_alloc_frame();
pTempFrame->pts = 0;
pOutFormat = NULL;
pFormatContext = NULL;
pVideoStream = NULL;
pAudioStream = NULL;
bool res = false;
// Create format
switch (type) {
case MyVideoEncoder::H264:
pOutFormat = av_guess_format("h264", NULL, NULL);
break;
case MyVideoEncoder::MPEG1:
pOutFormat = av_guess_format("mpeg", NULL, NULL);
break;
default:
pOutFormat = av_guess_format(NULL, pathToMovie.c_str(), NULL);
break;
}
if (!pOutFormat) {
pOutFormat = av_guess_format(NULL, pathToMovie.c_str(), NULL);
if (!pOutFormat) {
std::cout << "output format not found" << std::endl;
return false;
}
}
// allocate context
pFormatContext = avformat_alloc_context();
if(!pFormatContext)
{
std::cout << "cannot alloc format context" << std::endl;
return false;
}
pFormatContext->oformat = pOutFormat;
memcpy(pFormatContext->filename, pathToMovie.c_str(), min( (const int) pathToMovie.length(), (const int)sizeof(pFormatContext->filename)));
//Add video and audio streams
pVideoStream = AddVideoStream(pFormatContext,
pOutFormat->video_codec);
// Set the output parameters
av_dump_format(pFormatContext, 0, pathToMovie.c_str(), 1);
// Open Video stream
if (pVideoStream) {
res = openVideo(pFormatContext, pVideoStream);
}
if (res && !(pOutFormat->flags & AVFMT_NOFILE)) {
if (avio_open(&pFormatContext->pb, pathToMovie.c_str(), AVIO_FLAG_WRITE) < 0) {
res = false;
std::cout << "Cannot open output file" << std::endl;
}
}
if (res) {
avformat_write_header(pFormatContext,NULL);
}
else{
freeMemory();
std::cout << "Cannot init encoder" << std::endl;
}
return res;
}
AVStream *MyVideoEncoder::AddVideoStream(AVFormatContext *pContext, CodecID codec_id)
{
AVCodecContext *pCodecCxt = NULL;
AVStream *st = NULL;
st = avformat_new_stream(pContext, NULL);
if (!st)
{
std::cout << "Cannot add new video stream" << std::endl;
return NULL;
}
st->id = 0;
pCodecCxt = st->codec;
pCodecCxt->codec_id = (CodecID)codec_id;
pCodecCxt->codec_type = AVMEDIA_TYPE_VIDEO;
pCodecCxt->frame_number = 0;
// Put sample parameters.
pCodecCxt->bit_rate = outWidth * outHeight * 3 * frameRate/ compressionFactor;
pCodecCxt->width = outWidth;
pCodecCxt->height = outHeight;
/* frames per second */
pCodecCxt->time_base= (AVRational){1,frameRate};
/* pixel format must be YUV */
pCodecCxt->pix_fmt = PIX_FMT_YUV420P;
if (pCodecCxt->codec_id == CODEC_ID_H264)
{
av_opt_set(pCodecCxt->priv_data, "preset", "slow", 0);
av_opt_set(pCodecCxt->priv_data, "vprofile", "baseline", 0);
pCodecCxt->max_b_frames = 16;
}
if (pCodecCxt->codec_id == CODEC_ID_MPEG1VIDEO)
{
pCodecCxt->mb_decision = 1;
}
if(pContext->oformat->flags & AVFMT_GLOBALHEADER)
{
pCodecCxt->flags |= CODEC_FLAG_GLOBAL_HEADER;
}
pCodecCxt->coder_type = 1; // coder = 1
pCodecCxt->flags|=CODEC_FLAG_LOOP_FILTER; // flags=+loop
pCodecCxt->me_range = 16; // me_range=16
pCodecCxt->gop_size = 50; // g=250
pCodecCxt->keyint_min = 25; // keyint_min=25
return st;
}
bool MyVideoEncoder::openVideo(AVFormatContext *oc, AVStream *pStream)
{
AVCodec *pCodec;
AVCodecContext *pContext;
pContext = pStream->codec;
// Find the video encoder.
pCodec = avcodec_find_encoder(pContext->codec_id);
if (!pCodec)
{
std::cout << "Cannot found video codec" << std::endl;
return false;
}
// Open the codec.
if (avcodec_open2(pContext, pCodec, NULL) < 0)
{
std::cout << "Cannot open video codec" << std::endl;
return false;
}
return true;
}
bool MyVideoEncoder::configureFrames() {
/* alloc image and output buffer */
outbuf_size = outWidth*outHeight*3;
outbuf = (uint8_t*) malloc(outbuf_size);
av_image_alloc(pTempFrame->data, pTempFrame->linesize, pVideoStream->codec->width,
pVideoStream->codec->height, pVideoStream->codec->pix_fmt, 1);
//Alloc RGB temp frame
pFrameRGB = avcodec_alloc_frame();
if (pFrameRGB == NULL)
return false;
avpicture_alloc((AVPicture *) pFrameRGB, PIX_FMT_RGB24, inWidth, inHeight);
pFrameRGB->pts = 0;
//Set SWS context to convert from RGB images to YUV images
if (img_convert_ctx == NULL) {
img_convert_ctx = sws_getContext(inWidth, inHeight, PIX_FMT_RGB24,
outWidth, outHeight, pVideoStream->codec->pix_fmt, /*SWS_BICUBIC*/
SWS_FAST_BILINEAR, NULL, NULL, NULL);
if (img_convert_ctx == NULL) {
fprintf(stderr, "Cannot initialize the conversion context!\n");
return false;
}
}
return true;
}
void MyVideoEncoder::closeEncoder() {
av_write_frame(pFormatContext, NULL);
av_write_trailer(pFormatContext);
freeMemory();
}
void MyVideoEncoder::freeMemory()
{
bool res = true;
if (pFormatContext)
{
// close video stream
if (pVideoStream)
{
closeVideo(pFormatContext, pVideoStream);
}
// Free the streams.
for(size_t i = 0; i < pFormatContext->nb_streams; i++)
{
av_freep(&pFormatContext->streams[i]->codec);
av_freep(&pFormatContext->streams[i]);
}
if (!(pFormatContext->flags & AVFMT_NOFILE) && pFormatContext->pb)
{
avio_close(pFormatContext->pb);
}
// Free the stream.
av_free(pFormatContext);
pFormatContext = NULL;
}
}
void MyVideoEncoder::closeVideo(AVFormatContext *pContext, AVStream *pStream)
{
avcodec_close(pStream->codec);
if (pTempFrame)
{
if (pTempFrame->data)
{
av_free(pTempFrame->data[0]);
pTempFrame->data[0] = NULL;
}
av_free(pTempFrame);
pTempFrame = NULL;
}
if (pFrameRGB)
{
if (pFrameRGB->data)
{
av_free(pFrameRGB->data[0]);
pFrameRGB->data[0] = NULL;
}
av_free(pFrameRGB);
pFrameRGB = NULL;
}
}